The Hybridoma Library/Monoclonal Antibody Production Shared Resource (Hybridoma Shared Resource) provides NCCC investigators with quality-controlled monoclonal antibodies (mAbs) as purified proteins an d/or supernatants from hybridoma cell lines that have been obtained from the ATCC or from individual investigators. This facility maintains characterized and quality-controlled stocks of supematants and monoclonal antibodies from more than one hundred cell lines. It is especially cost- effective for studies that require only a small sample of a given antibody and would otherwise result in a charge to individual grants of $250 to $500 per antibody. This Resource also advises investigators on both the creation of new hybridomas and the production and purification of large quantities of antibodies as needed. During the past year this Resource was used exclusively by NCCC investigators; there is no charge-back system for supply of these antibodies, which often come from patented cell lines. Over the past year, this Shared Resource is estimated to have achieved a net savings of between $41,000 and $100,000 over the commercial cost of comparable antibodies.